For improving the appearance aesthetics of liquid crystal displays (LCDs) and increasing the area having “touch-move” function, narrow-bezel LCDs are hotspot in LCD panel researches. One technical problem during the manufacture of narrow bezel LCD panels is how to reduce the width of sealant for bonding substrates.
The width of sealant in existing LCD panels is generally between 0.7 and 1.0 mm, while the width of sealant in narrow bezel LCD panel products can be usually 0.5 mm or less. With respect to sealants having a width of 0.5 mm or less, the coating linearity is especially important. FIG. 2 shows a morphology of a traditional sealant with a coating width of 0.5 mm as observed under microscope. From the photomicrograph, it can be seen that the 0.5 mm-wide traditional sealant exhibits, when coated, irregular zigzag edges and poor linearity, which may result in relatively large fluctuations of the sealant width, and affect the bonding property and liquid crystal impact resistant property of the sealant.
Chinese Patent Application Publication No. 103205216A discloses a sealant and a method of preparing the same. The sealant comprise 60-70 wt % of a low-viscosity epoxy acrylic photocurable resin; 1-5 wt % of an epoxy resin; 0.5-1 wt % of a photoinitiator; 5-10 wt % of a thermocuring agent; 1-2 wt % of a coupling agent; 5-10 wt % of organic powders; 5-10 wt % of inorganic powders; and 1-5 wt % of porous glass microspheres treated with inert gas. The method comprises: (1) mixing the components for constituting the sealant to give a mixture; (2) compounding the mixture; and (3) degassing the compounded mixture. The sealant of that application can inhibit the occurrence of liquid crystal puncturing phenomenon in LCD panels when coated around the periphery of underlying substrates because it comprises porous glass microspheres treated with inert gas.
However, although the aforesaid technical solution good performances for solving the puncturing defect problem, the overall property thereof is still required to be improved since it comprise an epoxy resin and a thermocuring component, while the size range of filler component is unfavorable for the linearity of coated sealant.
Thus, there is still a need of sealant compositions having improved coating linearity.